The colorectal cancer is the cancer of the colon and the rectum. The colon is the 4 to 6 feet long section in the large intestine or the second-half of our tubular digestive tract. The rectum is the 4 to 6 inches long small tube that comes at the end of the colon and just before the anus. Together, it is called the ‘colorectal tube.’ It is a fertile growing ground for polyps or small tumor like growths. Not all polyps are cancers, as they start as benign tumors, but the colorectal cancer develops from these polyps.
What is Colorectal Cancer?
Colorectal cancer is a type of cancer that forms either in the colon or in the rectum, from polyps that are formed in the inner lining of the lower part of large intestine.
Stages of Colorectal Cancer
Depending on how far the cancer has spread on the inner wall of the intestine, colorectal cancer can be divided into different stages. To determine the stage of colorectal cancer, physical examination, biopsy and different imaging tests are done. Staging of the cancer helps the doctor to determine the treatment procedure of colorectal cancer.
Stage 0 Colorectal Cancer: When the cancer is found only in the innermost lining of your colon, it will be deemed as the stage 0 colorectal cancer. In this stage, the treatments include removal of the tumor and little of the surrounding tissue with a local excision. Anastomosis is also done to remove the diseased part of the colon in case of large colon cancer.
Stage-I Colorectal Cancer: When the tumour spreads beyond the inner lining of the colon and involves the second and third layer of the colon, it is deemed as the stage-I colorectal cancer. In this cancer stage, the cancer stays within the inside wall of the colon and does not spread to the outer walls. Surgical removal of the tumour and some of the tissues surrounding it are the normal treatment procedures. At this stage of colorectal cancer, no aggressive surgery is needed. According to the reports of the American Cancer Society, about 93% people who are diagnosed with stage-I colorectal cancer are seen to have an easy 5 year survival rate. It offers a great potential for cure to those with stage-I colorectal cancer.
Stage-II Colorectal Cancer: When the cancer extends through the muscular wall and is a large mass of cancerous cells, it is known as the stage II colorectal cancer. However, in this stage, the cancer does not affect the lymph nodes. Surgery and removal of the cancerous cells and the surrounding areas is the standard treatment procedure in this stage of colorectal cancer. However, in many cases, chemotherapy is given to make sure that the colorectal cancer does not recur; although, whether it is required or not is the decision of a skilled oncologist.
Stage-III Colorectal Cancer: When the cancer spreads out of the colon and reaches and affects the lymph nodes (one or many), it is called the stage-III of colorectal cancer. This stage also has a few sub-stages and they are – stage IIIA in which the tumour stays within the colon wall, but affects the lymph nodes; stage IIIB in which the tumour grows through the wall of the colon and affects up to four lymph nodes and stage IIIC in which the tumour grows through the wall of the colon and affects more than 4 lymph nodes. Treatment for stage III colorectal cancer includes: surgical removal of the tumour, chemotherapy with drugs such as Leucovorin, 5-FU, Oxaliplatin and Capecitabine separately or together. If the cancer is spreading to the surrounding tissue, radiation therapy is also given.
Stage-IV Colorectal Cancer: When the colorectal cancer spreads to other parts of the body, like to the lungs and the liver, it is considered as the stage-IV colorectal cancer. This stage of colorectal cancer is also known as ‘metastatic’ cancer stage. In this colorectal cancer stage, it is not necessary that the cancer will have to spread to the lymph nodes and can be of any size. The treatment for stage-IV colorectal cancer includes: surgical removal of the cancerous colon, removal of the other body parts to which the cancer has spread and chemotherapy to improve survival and radiation therapy to relieve the cancer symptoms.
What are the Causes of Colorectal Cancer?
The exact cause of colorectal cancer is unknown. The cancer destroys the normal cell growths and tissue. The potential causes of colorectal cancer include:
Precancerous Growths in the Colon: When mushroom shaped or flat looking polyps occur in the colon, it is the most prominent cause for colorectal cancer to occur. Hence, removal of these polyps is the most beneficial decision to prevent colorectal cancer from developing.
Gene Mutations: Genetic makeup is also one of the primary causes of colorectal cancer. MAP or MYH-associated polyposis and FAP or Familial Adenomatous Polyposis, are genetic causes that can lead to colorectal cancer. Diseases associated with the genes, such as Turcot’s syndrome, Gardner’s syndrome, juvenile polyposis, Peutz-Jagher’s syndrome and Cowden’s disease can also cause this cancer.
Diet: Diets full of meat and saturated fat and rich in proteins will cause a high risk of colorectal cancer. Those, who consume diets with fruits and vegetables are at a lower risk for colorectal cancer.
Chemical Exposure: When you are exposed to chlorine and asbestos in any form, your body is most likely to develop these kinds of cancerous developments.
Who is at Risk for Colorectal Cancer?
The people, who are at high risk of developing colorectal cancer are:
- People, who have crossed their age of 60, are more at risk for colorectal cancer.
- A habit of regular smoking and alcohol intake is also a risk factor for colorectal cancer.
- Those, who have a family history of this disease, are also at risk for colorectal cancer.
What are the Symptoms of Colorectal Cancer?
Colorectal cancer does not have any external and physical expression of the cancerous polyp. However, there are few signs and symptoms that can indicate the possibility of a cancerous polyp in the colon or in the rectum, or both. These colorectal cancer symptoms are:
- Persistent occurrence of diarrhea that will stay for a few days at a stretch.
- Persistent constipation that would not be cured.
- Gas, bloating, lower abdominal cramps.
- Different looking and different smelling stool.
- Thin faeces or ‘pencil stool.’
- Blood in stool (rectal bleeding or dark stool).
- Persistent discomfort in the lower abdomen with killer pain.
- Passing a large amount of blood through anus.
- Unexpected and involuntary weight loss.
However, along with these signs and symptoms of colorectal cancer, there is one more thing that must be kept in mind and that is – there can be no symptoms from colorectal cancer at all.
Prognosis, Survival Rate & Epidemiology of Colorectal Cancer
More than 1 million people get colorectal cancer globally every year. In statistical surveys, it came up that the deaths caused by colorectal cancer numbered 715, 000 in the year 2010. Studies made in the year 2012 showed that colorectal cancer is the second common cause of cancer in women all over the world and third common cause of cancer in men. Around 40,000 new cases of colorectal cancer are diagnosed every year in the United Kingdom. In the United States of America on the other hand, the number of new cases of colon cancer is 93,090 and the number of new cases of rectal cancer is 39,610.
The survival rate of colorectal cancer varies to a great extent and largely depends on the time of diagnosis, the stage of the cancer and how the patient responds to treatment. As per the reports of the National Cancer Institute, patient who are diagnosed with stage-I colorectal cancer, have a survival rate up to 93%. Whereas, the survival rate varies within 72% to 85% for those who are diagnosed with stage-II colorectal cancer. Survival rate for stage III colorectal cancer is about 44 to 83% and only 8% for those, who are diagnosed with stage-IV colorectal cancer. When the colorectal cancer spreads to the lymph nodes and other body parts, there is high possibility that the cancer will recur. Hence, despite aggressive treatment, the chances for survival reduce radically in advanced stages of colorectal cancer.
How is the Diagnosis for Colorectal Cancer Made?
If you exhibit signs and symptoms of for colorectal cancer, the doctor will recommend further diagnostic tests which include:
Colonoscopy: In this process, a long, flexible and slender tube is inserted through the rectum to check the inside of the colon. A video camera is attached at the tip of the tube that helps the doctor to check if any polyp or tumour growth has occurred in the rectum and colon.
Biopsy: With the same colonoscopy tube, a small sample of the polyp tissue is collected to check for the presence of cancerous cells. Biopsy is the sure shot method to diagnose for colorectal cancer.
CT Scan: To take images of the tumour, CT scan is done to confirm the diagnosis of colorectal cancer.
What is the Treatment for Colorectal Cancer?
Surgery: Surgical removal of the cancerous polyp or tumour is the first treatment that is given to the patient suffering from for colorectal cancer. It ensures that the source of the cancer is removed.
Chemotherapy: When the colorectal cancer is in its stage II and onwards, chemotherapy is given by the oncologist. Chemotherapy helps to get rid of the symptoms of colorectal cancer and prevents the cancer from spreading to other tissues and organs. A combination of different cancer fighting drugs is given in this treatment process for colorectal cancer.
Radiation Therapy: When cancer is spread to other organs or tissues of the body, radiation therapy is given to destroy or kill the cancer cells. In this process, the healthy cells are also damaged by default. Hence, to prevent the symptoms and support the system to work normally, radiation therapy is given along with chemotherapy for treating colorectal cancer.
Colon and rectal cancers are common and occurs in 1 individual in almost every 20 people. However, with early screening and diagnosis, colorectal cancer can be well managed and treated. A proper treatment must be given to the patient according to the stage of colorectal cancer diagnosed. It can be emotionally distressing to know about this disease. However, with proper palliative care, colorectal cancer can be managed and coped with. As you talk and stay close to your near and dear ones, it will help you to understand that colorectal cancer is not the end of the world and there is nothing to lose hope. Yet, prevention is always better than cure; and hence, a healthy life style, avoiding saturated fats and protein as well as staying away from alcohol and smoking will certainly help to reduce the risk of colorectal cancer and other cancers and diseases as well.